Protein incorporated flower-shaped hybrid nanostructures have received highly considerable attention due to their greatly enhanced catalytic activities and stabilities. Up to date, proteins, enzymes ...(mostly considered as proteins), and amino acids (as the building blocks of peptides and proteins) have been used as organic components of the hybrid nanoflowers. Herein, we present a rational strategy to rapidly form catecholamines (dopamine, epinephrine and norepinephrine)-copper ion (Cu
) incorporated nanoflowers (cNFs) mostly in 3 hours and show their peroxidase-mimic catalytic, dye degradation and antimicrobial activities through Fenton-like reaction mechanism. We systematically studied effects of experimental parameters including catecholamine concentrations, reaction time and reaction pH values, on formation of the cNFs. We also explained that norepinephrine nanoflower (neNF) with its porous structure, high surface area, polar surface property behaves as an efficient Fenton agent by exhibiting highly much catalytic activities compared to dopamine nanoflower (dNF) and epinephrine nanoflower (epNF). We claim that the NFs formed using nonprotein molecules can be used in designing new generation nanobiocatalytics, antimicrobial agents, nanobiosensors and pharmaceutical products.
Catalytic activity and stability of HRP‐Cu2+ hybrid nanoflowers (hCu‐NFs) in the polymerization reactions of phenol derivatives was investigated. It was observed that the catalytic activity and ...stability of hybrid nanoflowers on the polymerization of the phenol derivatives was considerably higher compared to free Horseradish peroxidase (HRP) enzyme. The hCu‐NFs effectively polymerized phenolic compounds as a novel nanobiocatalyst and led to polymers having quite high yields, molecular weights, and thermal stabilities compared to free HRP enzyme. The hCu‐NFs provide substantial repeated use and showed some degree of catalytic activity even after fourth cycle experiment in the polymerization reactions.
Herein, the synthesis of bovine serum albumin-Cu(II) hybrid nanoflowers (BSA-NFs) through the building blocks of bovine serum albumin (BSA) and copper(II) ions in phosphate buffered saline (PBS) and ...their use as adsorbent for cadmium and lead ions are reported. The BSA-NFs, for the first time, were efficiently utilized as novel adsorbent for solid phase extraction (SPE) of cadmium and lead ions in water, food, cigarette and hair samples. The method is based on the separation and pre-concentration of Cd(II) and Pb(II) by BSA-NFs prior to determination by slurry analysis via flame atomic absorption spectrometry (FAAS). The analytes were adsorbed on BSA-NFs under the vortex mixing and then the ion-loaded slurry was separated and directly introduced into the flame AAS nebulizer by using a hand-made micro sample introduction system to eliminate a number of drawbacks. The effects of analytical key parameters, such as pH, amount of BSA-NFs, vortexing time, sample volume, and matrix effect of foreign ions on adsorbing of Cd(II) and Pb(II) were systematically investigated and optimized. The limits of detection (LODs) for Cd(II) and Pb(II) were calculated as 0.37 μg L−1 and 8.8 μg L−1, respectively. The relative standard deviation percentages (RSDs) (N = 5) for Cd(II) and Pb(II) were 7.2%, and 5.0%, respectively. The accuracy of the developed procedure was validated by the analysis of certified reference materials (TMDA-53.3 Fortified Water, TMDA-70 Fortified Water, SPS-WW2 Waste Water, NCSDC-73349 Bush Branches and Leaves) and by addition/recovery analysis. The quantitative recoveries were obtained for the analysis of certified reference materials and addition/recovery tests. The method was successfully applied to the analysis of cadmium and lead in water, food, cigarette and hair samples.
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•The synthesis of bovine serum albumin-Cu(II) hybrid nanoflowers is reported.•The nanoflowers were utilized for solid phase microextraction of Cd and Pb.•The effects of analytical parameters were systematically investigated and optimized.•The method has been applied to the analysis of cadmium and lead in real samples.
In the context of the proposed work, two different amino acids (Glycine, Phenylalanine) have interacted with copper ions in a phosphate buffer (PBS) in place of enzymes. This interaction resulted in ...the nucleation of copper phosphate crystals and the formation of flower‐shaped amino acid‐copper hybrid nanostructures (AA‐hNFs), which grew through self‐assembly. While Cu (II) ions in the structure of AA‐hNFs were used as Fenton's agent for the catalytic activity. SEM, energy dispersive X‐ray spectroscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy measurements were used to define the AA‐hNFs′ characterisation. The peroxidase‐like activities of AA‐hNFs were investigated by UV/VIS spectrophotometer. Metal nanoparticles have peroxidase‐like activity. A class of enzymes known as peroxidases is able to catalyze the conversion of hydrogen peroxide into hydroxyl radicals. These radicals also take part in electron transfers with substrates, which results in color during oxidation. When cupric oxide nanoparticles are added to the peroxidase substrate while H2O2 is present, a blue color product with a maximum absorbance at=652 nm can result, demonstrating the catalytic activity of a peroxidase. The morphology and composition of AA‐hNFs were carefully characterized and the synthesized parameters were optimized systematically. Results showed that the nanoparticles were dispersed with an average diameter of 7–9 μm and indicated a uniform flower shape. The results of the investigation are anticipated to significantly advance a number of technical and scientific sectors.
In this work, we developed novel colorimetric biosensors consisting of anthocyanin-rich either black carrot (
Daucus carota
ssp. sativus var. atrorubens Alef.) or red cabbage (
Brassica oleracea
) ...extracts for rapid, sensitive, and economic detection of
Helicobacter pylori
(
H. pylori
). We comparatively prepared two test solutions as biosensors including anthocyanin-rich black carrot extract (Anth@BCE) and red cabbage extract (Anth@RCE), both of which fixed to pH 2.5 and investigated their colorimetric responses based on electronic structure and electron density of anthocyanins. We successfully used anthocyanin-rich BCE and RCE as natural pH indicators in detection of
H. pylori
and introduced their advantages like non-toxicity, easy accessibility, and high stability compared to synthetic indicators. The BCE and RCE tests gave the best color change in the presence of 10
3
CFU/mL (at 60 min) and 10
4
CFU/mL (at 75 min)
H. pylori
suspensions prepared in an artificial gastric fluid. The limit of detection was down to 10 CFU/mL for RCE and BCE tests by increasing incubation time (≥ 5 h). We further made an additional study that color differences in the colorimetric responses observed by naked eyes were supported by digital image processing with RGB (Red Green Blue) and Delta-E (ΔE) analysis. It is confirmed that results evaluated by naked eyes and digital image processing are well consistent with each other. These findings proposed that these colorimetric tests can be implemented to pH dependent detection of various microorganisms and can be effectively transferred from laboratory work to clinics in the near future.
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•Plant extract Viburnum opulus (VO)-inorganic hybrid nanosnowballs (NSBs) were prepared for the first time.•The NSBs exhibited much antimicrobial activity towards various bacterial ...and fungal pathogens compared free VO extract.•The NSBs acted as Fenton-like reagents to show catalytic activity against guaiacol in the presence of H2O2.
Herein, we report the production of novel organic-inorganic nanobio-catalytic and antimicrobial agents called “nanosnowball” (NSBs) with a rational design and elucidate the increase in the catalytic and antimicrobial activities. The NSBs resemble to guelder rose were formed of the extract of Viburnum opulus (VO) as the organic component and copper (II) ions (Cu2+) as the inorganic component. The effects of the VO extract and Cu2+ concentrations on the morphology of NSBs were systematically examined and characterized with several techniques such as SEM, FT-IR, EDX and XRD. Our results demonstrated that the presence of CuO bonds in NSBs could be indication of VO extract-Cu2+ complexes. Interestingly, the NSBs exhibited peroxidase-like activity towards guaiacol used as a model substrate depending on Fenton-like reaction. While free VO extract did not show antimicrobial activity at indicated concentration (2000–125μg/mL), the NSBs showed effective antimicrobial activity against bacterial (Escherichia coli ATCC 35218, Salmonella typhi ATCC 14028, Enterococcus faecium ATCC 8459, Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923, except Pseudomonas aeruginosa ATCC 27853 and Haemophilus influenza ATCC 49247) and fungal pathogens (Candida albicans ATCC 10231, C. glabrata ATCC 90030), respectively.
We report a green approach to synthesize lactoperoxidase (LPO) enzyme and metal ions hybrid nanoflowers (HNFs) and investigate mechanism underlying formation and enhanced catalytic activity and ...stability under different experimental parameters. The HNFs formed of LPO enzyme purified from bovine milk and copper ions (Cu2+) were synthesized at two different temperatures (+4°C and 20°C) in PBS (pH 7.4). The effects of experimental conditions, pH and storage temperatures, on the activity and stability of LPO–copper phosphate HNFs were evaluated using guaiacol as a substrate in the presence of hydrogen peroxide (H2O2). Optimum pHs were determined as pH 8 and pH 6 for LPO–copper phosphate HNF and free LPO, respectively. LPO–copper phosphate HNF has higher activity than free LPO at each pHs. Activities of LPO–copper phosphate HNF at pH 6 and pH 8 were calculated as 70.48EU/mg, 107.23EU/mg, respectively while free LPO shows 45.78EU/mg and 30.12EU/mg, respectively. Compared with free LPO, LPO–copper phosphate HNFs exhibited ∼160% and ∼360% increase in activities at pH 6 and pH 8, respectively. Additionally, LPO–copper phosphate HNFs displayed perfect reusability after six cycles. Finally, we demonstrated that LPO–copper phosphate HNFs can be utilized as a nanosensor for detection of dopamine and epinephrine.
Enzyme catalyzed reactions are known to be environmental friendly and easy method for many applications. However, utilization of enzymes in a variety of reactions is strictly limited due to their ...high cost, instability in aqueous solutions, denaturation in organic solvents and high temperatures. For this reason, it is important to discover new generation catalyst systems indicating enzyme‐like catalytic activity. Here, we report hybrid organic–inorganic flower‐shaped green tea‐Cu2+ nanobiocatalyst synthesized from green tea extract as an organic component and copper (II) ions (Cu2+) as inorganic component. The effect of the peroxidase‐mimicking activity of green tea‐Cu2+ nanobiocatalyst was investigated on the polymerization of phenol and derivatives (guaiacol and salicylic acid) through Fenton‐like reaction mechanism. Obtained successful outcomes showed that the synthesized nanobiocatalyst showed very high catalytic activity upon polymerization of phenol and guaiacol. The slight solubility of salicylic acid in water limited to achieve its polymerization under‐performed reaction conditions. The yields and molecular weights of the obtained polymers were found to be quite high. While free peroxidase enzymes like horseradish peroxidase (HRP) enzyme loses its catalytic activity at 60°C and above temperatures, green tea‐Cu2+ nanobiocatalyst exhibited very high catalytic activity upon polymerization reactions even at 60°C reaction temperature. This outcome provides significant advantages in some reactions requiring high temperatures. In order to understand the origin of the catalytic activity of the green tea‐Cu2+ nanoflowers, similar biocatalysts were also synthesized from caffeine and catechin alkaloids which are the active components of green tea. Caffeine‐Cu2+ and catechine‐Cu2+ nanobiocatalysts also exhibited quite high catalytic activity toward polymerization of phenol and derivatives. We suggest that green tea‐Cu2+ and similar types of nanobiocatalysts may expand their utilization in polymer chemistry as promising catalytic agents for radicalic polymerizations.
The discovery of functional organic-inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(
ii
) ion as the inorganic component has made an enormous ...impact on enzyme immobilization studies. The FNFs synthesized by an encouraging and novel approach not only showed high stabilities but also much enhanced catalytic activities as compared to free and conventionally immobilized enzymes. A recent development demonstrated that FNF formation has moved beyond the initial discovery in which enzymes and Cu
2+
ions used as the organic and inorganic parts, respectively, are replaced with new organic (chitosan, amino acid and plant extracts) and inorganic (Cu
2+
and Fe
2+
) materials. The new organic materials incorporated into FNFs act as Fenton-like agents and then show peroxidase-like activity owing to the metal ions and the porous structure of FNFs in the presence of hydrogen peroxide (H
2
O
2
). All FNFs have been widely utilized in many different scientific and industrial fields due to their greatly enhanced activities and stabilities. This review focuses primarily on the preparation, characterization, and bioanalytical applications of FNFs and explains the mechanisms of their formation and enhanced activities and stabilities.
The discovery of functional organic-inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(
ii
) ion as the inorganic component has made an enormous impact on enzyme immobilization studies.
Due to its distinct, atypical features and possible applications, three-dimensional (3D) hierarchical nanoflowers have sparked considerable interest. Copper (II) ions were employed as inorganic ...components in this study, whereas various extracts from Aspergillus terreus and their extracted main components were used as organic components. Extracts from A. terreus and its isolated principal component molecules can first form complexes with copper ions, and these complexes subsequently become nucleation sites for primary copper phosphate crystals, showing interactions using an easy and successful self-assembly template synthesis technique. Therefore, the process results in the formation of 3D nanoflowers among the A. terreus extract and its remoted important additives in addition to copper ions, ensuing in a completely unique round flower-like shape containing loads of nanopetals under the most excellent conditions along with pH, attention of organic–inorganic additives, temperature, and the quantity of copper nitrate on nanoflower formation. Furthermore, A. terreus and its isolated major components, Cu3(PO4)2 nanoflowers, seemed to have a remarkable antibacterial effect. Our findings highlight the benefits of nanoflowers made with A. terreus and its isolated secondary metabolites of inorganic structures, which could be used in industrial biocatalysts, biosensors, and environmental chemistry.
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